Lens-chuck.



l. H. COSSMAN.

LENS CHUCK.

APPLlcATloN man Nov.16, 1914.

l ,296,050. Patented Mar. 4,1919.

2 SHEETS-SHEET l.

J. H. CUSSMAN.

LENS CHUCK.

APPLncATloN FMD Nov.15,1914.

l ,2961,050. Patented Mar. 4,1919.

l 2 SHEETS-SHEET 2.

WRI

W WITNSSES gasolene, or some other grlnding and has -excessive on account of the factl leuca 'ro run orrrcer. aronn'rron or new roux.

arles-omrek.v

assente.

To all whom it may concern: Y J

Be it known that I, JOSEPH H. CossMAN,

a citizen of the United States of America, and a resident of -Perth Amboy, county of Middlesex, and State of New Jersey, 'have invented certain'new and useful Improvements in Lens-Chukgof-which the following is a specification, reference being had to the accompanyingdrawings, forming apart thereof.

My invention pertains to the art of lens special reference to means r holding the lens blank during the process of grinding optical lenses. he rough pieces'of glass fromwhich optical lenses are ground have hitherto been supported during the grindin process, by to small metal ace plates by Suitable 'cement. The cementing of the face plate necessarily required time and skill, and furth by reason of the breakage considerable ermore, the losses that the pitch had to be applied hot to the two surfaces after both the gla and the face plate were heated. After the glass was secured to the face plate and the grinding operation well under way, grinding friction was frequently sufficient to melt the pitch and loosen the lens from the face plate, necessitating the cementing process to be done over. v

After the lens has been successfully ground in the aforesaid manner there is a further diiiiculty in separating the lens from the face plate and cleaning the pitch from the back surface which was finished first. This has chilling in cold Water, then striking the back of the face plate to crack the pitch. ere again the lens is liable to be broken. hen successfully must be cleaned by carefully finally dissolving off the remainder with suitable solvent. The difficulties and expense involved in this process are evidently great.

Another diiliculty has been to pitch the lens onto the face .plate in a central position and parallel to the surface of the plate.

Epecication of Letters Patent. application mearrovember 16,1914. serial no. amaca.

glass to vthe of 'the glass were` the heat generated by the Y been accomplished by first separated from the face y plate one surface is covered with pitch and scrapingy and la portion' of instead of by rammed man?. aime.

with an uneven Frequentl the lens -is Set of center, and must pitch of breakage or interference with the work during the grinding process.

Another object is to provide a device of the aforesaid character that shall be particularlyarranged and comprise a plurality of parts especially adapted for the peculiar conditions of service under which it is utilized. v Other objects and advantages of my invention will be set forth. hereinafter, and in order that my invention may be thoroughly I -will now proceed to describe Referring to the drawings:

'Figure 1 lis a sectional lelevation of a grinding tool showing the lens chuck of my invelntion as utilized in connection therewit Fig. 2 is a transverse Asectional elevation of the same chuck. v l

Fig. 3 is a plan view of the chuck with'the top plate broken away and shown in section. to bring out the position and form of the slots in which the chuck jaws are mounted.

Fig. 4 is a View corresponding to Fig. 2 of the body member of the chuck. l

Figs. 5, 6, 7 8 and 9 are detail views showing other parts of the device. l Fig. 10 is a sectional plan view showing a modified chuck in which the Aadjusting screws are held in position by pins a split ring as in the previous gures.

...Fig 11 is a view corresponding to Fig.V

provide a simple i or other cement, and without danger 15 which a cylinderis tobe ground.

2, of another chuck structure which also emthe perspective view, Fig. 8, and attention bodies my invention. z particularly directed to the fact that. it has' Fig. 12.illustrates a'center which maybe an upwardly .extending projection 42 hav-l substituted for the center` of Fig. 11 when ing sharp inclined teeth 43 which are adapta convex lens is to be ground. y

Fig. 13 shows a removable bed which is as shown in Fig. 2. convex in curvature and is .adapted to be The projections 34 and 37 of the block 20 utilized for the grinding of a convex lens. and the outer surfaces ofthe projections 42 Figs. 14 and 15 are sectional views showareall curved so as to avoid outwardly proing convex and concave beds which may be truding corners or projections, and the cover 75 substituted for the bed illustrated in Fig. 2.' ring 27 i s arranged to inclose the headsV of Fig. 16 is a back view of a chuck which isl the screws because the lens chuck rotates at provided with three recesses instead of one a relatively high speed during the grinding and is adapted `for holding a lens blank in process, and it is therefore desirable that it j shall present as smooth a surface as pos- 80 Referring particularly to Figs. 1,to9v in#v sible. elusive, the structure here shown comprises vThe bed is in the form .of a disk having a block 20 *having a plurality of radial slots a plane bottom surface -which is fitted into 21, jaws 22, adjusting screws 23 therefor, a the recess 33 in the block 2 0. Its outer sur- 20 'removable center 24, a removable bed 25, a' face is curved toconform to one surface of 85 divided supporting ring. 26, and a cover the lens which it is to support and is provv ring 27. v vided -.with a- -pad 44 of rubber sheeting or The block 2li-has -acentral opening 30 other. suitable material. As shown in Figs. which is enlarged at one end to form shoul- 14 and 15, the bed may be either concave or '25 ,ders 31 relatively close to the face of the convex and it is usual to provide a large 90 block. Radial holes 32 areprovided in the number of these simple partsto correspond inner ends of theslots 21 and constitute with the various curvatures desired forNoptibearings for-the inner ends of the adjusting cal 'lenses screws 23. A shallow recess 33 is' provided Before proceeding to the .description 4of in the face of the block to receive the bed 25. the modifications shown inthe other figures, 9.5

Projections 34 extend outwardly from the the method of using the lens chuck f0rgrind block-on each side of each slot 21 for the ing spherical lenses, will first be discussed. vpurpose, of guiding the jaws 22 as they are Referring particularlyto Fig. 1, 50 repreadjusted inwardly and outwardly. The slots sents a vgrinding tool vof a well known type 35 21 are arranged in two groups as clearly ,which 'usuallycom-prises adisk of cast iron 10 shown in Fig. 3v on oppositef sides of' the having an outer surface 51 which is spheri center so that comparatively wide spaces 36 cally curved, the radius of curvature being are left between grou-ps. determined by the curvature of the lens to While I have shownsix slotS,-three bebe ground. ,.This :cast iron tool having a 40 ing located on each side,-my invention iS smooth surfaceis rotated at a suitable speed 105 not restrictedto this number and someother and a mixture of emery and water 1s pour suitable number may be employed. onto its surface while the glass which is held -Projections 37 extend outwardly from the in the chuck, as shown 1n the drawing, is

. block at opposite points near the centers of being pressed against it bya bar 52. This the spaces 36. Theseproject'ons, together barispointed'at onejend which-engages the 110 with the projections 34, constitute a iiange cup-.shaped center 240i the chuck. The bar stop or shoulder against which the cover 52 constitutes apivotal supportfor the chuck ring. 27 is pressed.' The divided ring 26 is which is free to conform readily'to the sursplit into two ring sections 26a and 26 Which face of the tool 50 as the glass is ground, ar@ PI'OVided With Semi-Circular IIOCheS 38. and the grinding process consists of pressing 115 which are correspondingly located and conwith the bar 52 and at the same time moving stitute a plurality of outer bearings for the the chuck backward and forward from the adjusting screw 23 as clearly shown in Fig. 2. periphery to the center of the curved surface Each of the jaws 22 has a projection 39 of the tool. By reason of the motion of the at. which extends downwardly to the bottom of tool, the chuck, together with the' lens which 120 the slot 21 into which it is placed and has a it supports, are rotated about the point of radial tapped hole 40 through which one of the bar 52 as a pivot. v Y the adjusting screws 32 is threaded. The ar- The bar 52A may have a handle (not shown),

rangement of parts is such that by turning and be held in the hand of the operator or ed to cut into the edge surface of the glass 70 the head of the adjusting screw, which is it may be attached to an intermediate point 125' knurled, as shown at 41 and which is relain a lever which is pivotally supported at tively4 stationary, the jaw is moved radially one side of the machine and extends over the. inward and outward in the slot 21 .in which tool in a well known manner.

it is mounted. Attention is directed to the fact that the l5 The form of each jaw is clearly shown in cover ring 27 protects the adjusting screws 180 they are not clogged by -havlng'r'elatively large holes inepto l and other internal parts'of the chuck so `that the einery mixture W ich is poured over the chuck.

When the-center 24 is wornout. it--may be removed 'and replaced. j

be conveniently replaced by other centers in order to adapt it 'for grinding lenses of different curvatures, but I believe it will usually be' found preferableto utilize several chucks .havf 'centers located at different depths and hlilgapted for grinding lenses having different curvatures, it being understood that it is desirable -to'keep the point of the bar 52 as close tothe glass as possible, at all times, in order to avoid any tendency for the clhuck to sli out from under the point of t ebar.

Referring now toFig. 10, instead -of utilizing the divided ring 26, a single ring 26.

38 lized. Each of the holes 38.c ciently large-to receive the neck 53 of the a justing screw 23.v In justing screw is provided groove of semi-circular clearlys'hown in Fig. 10, with which Va`lock. ing pin 54 coperates to hold the screw in position4 withoutl interfering with its turnin 1n its bearin The ring 26 is provided with suitable holes to receive the pins 54. v

eferring now to with an annular cross-sectlon, 'as

having a centraltapped hole 6 1 andradial slots 62 corresponding to the slots 21; A

, disk 63 having' ai hollow cylindrical sleeve or projection 64-which is externallythr'eaded, is Vscrewed into tapped hole 61 of the block and the center 24 except removed and replaced by other centers such as that shown in Fig. 12,

curvature of .the lens which .1s belng .supported for. grinding. A bed 67 having aprois screwed into the hole 61 of the block from the top.- Its outer surface is curved to corre- Vjection 68 corresponding to the projection 64,.

tobe supported,` and is provided with a 69 corres onding to the pad 44.

One o the important advantages of this structure arises from the fact that thefbed may be raised or lowereduntil it is exactly adjusted to coperate with the chuck jaws in djustment lis to be ground convex the bed 67 may be turned to raise the blank slightly before the jaws 70 are set and thus insure that the jaws shall notinterfere with the grinding operation. The substitution of one bed for another is evidently only may be uti -4 f 'Other-beds, such as that is then sum! this form eaclrfad-V l When' the chuck 2. The g ass is rst Figs. 11, 12 and 13 thev g 65 to receive a remov- This center corresponds `tor that it is intended to be 4scribed d pending upon the the space 36 of the lens which is' pad -- and necessary when changes of curvature are. required.

Attention is further directed to the factA i surfaces of the jaws are bevl 'eled at the engaging The lcenter can be arranged so that it may Vbl are m ounted in the slots 62, but -insteadof radial holes 71 which have smooth bores and through which adjusting screws72 extend loosely. hese Vscrews are threaded into tapped holes 73 in the block 60 and the jaws may be pressed against the edge surface of the blank as shown in Fig. 11 by setting the screws. rlhe jaws however, must be pulled out after loosening the screws as they are not Vpositively moved by the turning of the screws.

shown in Fig. 13, bed 67 in order to surfaces having different may be substituted for the coperate with lens curvature.

is to 'support a lens which 1s to be ground'to a cylindrical curvature, it is .provided with three recesses -81-82 as shown in Fig. 16, each of which correspondsto the single center 24 of Figs. 1 and surfacedon a spherical to the tool 50 except that for holding the chuck and moving it backforward on the cylindrically e of an oscillating grinder such as is' employed curved lenses.

he arrangement of jaws as already deand as vclearly shown in Fig. 3, is particularly important ,and essential for grinding cylindrical lenses, since the blank ontwo opposite edges which are placed in is ground substantially to a laufe edge. he grinding process could therefore obviously not be completed if any vof the jaws vofthe chuck were locatedat these points.

For spherical work the jaws may be uniformly distributed if desired, and the chuck may then be used for cylindrical work by removing one pair of diametrically oppo- .site jaw n order to determine the thickness of the glass at various points notches 83484 are ocated in four quadrature points in the upper edge of the block, as shown in Figs. 3 known form of caliper (not shown) which is used for this purpose can readily be inserted in this slot while the other arm extends onto the top of the glass.

Attention is directed to the fact-that it is for grinding cylindrically dit Mld

lll@

possible touse pads on the lo@ surfaces we clamping jaws eachhavmg an inwardly in- -movable bed having a curved sur which materially reduce the losses due to breakage, and as already set forth it is evident that the Itime required for securing a suitable blank in the chuck for grinding, is insignificant.

rlhe blank may be prepared by grinding its edges Ion a bevel or in some other suitable manner to adapt it to be inserted in the chuck, but I consider this to be superfluous. I am aware that chucks have been utilized for various purposes but I believe that a chuck has never been known previous to my invention which was capable of being successfully used for the purpose for which my chuck is intended. It is obvious that the structure of my .device may be modified without departing from the spirit and scope of my invention, and I intend that only such limitations be imposed as are indicated in the appended claims.

What I claim is: v 1. A. lens holder comprising a chuck body, clamping jaws each having an inwardly inclined relatively sharp tooth projection to engage the'edge surface o the lens blank, means for adjusting the clamping jaws, a reace adapted to cooperate with one surface of the lens blank, and a socket center adapted to receive a pivotal pressure rod.

2. A lens holder comprising a chuck body,

clined relatively sharp tooth projection to engage the edge surface of the lens blank, means for adjusting the clamping jaws, a re- 3. A ens holder comprising a chuck body,

clamping members thereon, and an adjustable bed having a curvature to coperate with one surface of the lens to be ground,` said chuck body having a socket adapted to receive a. pivotal pressure rod.

4. 'A lens holder comprising a chuck body having a plurality of radial slots, clamping jaws mounted in said slots, means for setting `the jaws, abed having a`curved surface to coperate w1th one surface of the lens to .be

ound and having a proj eetion screwed into the body whereby the bed is adjustable, and a socket center adapted to receive a pivotal ressure rod. i

5'. A lens holder comprising a chuck body,

clamping jaws adjustably mounted therein and each having inwardly inclined relatively sharp toothed projections to engage thel edges of the lens, and a bed adjustably mounted upon the body whereby the'bed may adjust'a lens blank to coperate with the jaws.

In witness whereof, I have hereunto set my hand in the presence of two subscribing witnesses, this 12th day of November, 19M.

. JOSEPH H. COSSMAN.

Witnesses:

R. J. DEARBORN, F. Gamas. 

